I think long term trade is better than short term because trading is too much risky to all, so before starting trade you must have well knowledge about trading otherwise you will fall in loss. You may try to buy low rate and hold it until pump or reach new value..
If you are only trading for excess money,then i believe thats right long term trading is more safer and may give better profit
But if this area of profiteering will be use as your bread and butter,then maybe you must risk in daily trading,though you need more knowledge and skills to do this rightfully